PSY 1101 Final: PSY1101 Review Final Exam - Haddad
SchoolUniversity of Ottawa
Course CodePSY 1101
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Chapter 2: The Biology of the Mind
2-1: Why are Psychologists Concerned with Human Behavior?
Everything we do, every idea, every mood is a biological happening. Without the body, we would be
nothing at all. People often think of psychology and biology as two different streams, but it is very
important to think of them as the same thing, as psychology is a biological science.
The biology of the mind has come very far in the last few centuries. In the early 1800’s, phrenology, the
study of bumps on the skull was proposed. Although this idea proved incorrect, it led the way for
Localization of Function, the idea that different areas of the brain are associated with different functions
All brains follow the same basic principles. This allows researchers to study on relatively simple
organisms such as squids or sea slugs to find out how our own brain operates. Though the human brain is
much more complex than the brains of these simple organisms, they all follow the same principles.
2-2: Neurons –What are neurons and how do they transmit information?
The basic building block of the mind is the Neuron, or the nerve cell. Neurons allow for communication
between the brain and muscles, as well as thoughts and moods, but how do they work? How do they
communicate? There are various types of neurons, but they all have the same basic structure.
Soma: The cell body of a neuron. This provides everything and anything that a neuron needs to function
properly. It provides the cell with nutrients and expels waste.
Dendrites: The neuron’s bushy, branching extensions that serve two main purposes. 1) To increase the
surface area of the neuron. 2) To receive information from other neurons
Axon: A tail-like extension that passes messages between neurons by carrying the action potential.
Terminal Buttons or Axon Terminals: Nodes at the end of the axon that release neurotransmitters
Myelin Sheath: A fatty tissue that acts as insulation for the axon. The myelin sheath helps amplify the
action potential of a neuron. The myelin sheath gets laid down until about age 25. Neural efficiency,
judgement, and self-control grow in that time. If the myelin sheath somehow gets destroyed, multiple
sclerosis is the result. Communication to the muscles slow down, with eventual loss of muscle control
Synapse: Location where the neurons meet to communicate
Synaptic Cleft: The gap between two neurons at the synapse
Even though all neurons follow this basic structure, there are three different types of neurons, each with
their own specialized job
Sensory Neurons: These neurons gather information from the outside world, and relay the information to
the sensory areas of the brain
Motor Neurons: These neurons carry out information to the muscles, allowing for movement
Interneurons: These neurons, which are only found in the central nervous system, have the most
complex job out of all of the different types of neurons. They analyze, organize, and integrate
information, and there are billions of them.
Neurons transmit messages when stimulated by signals from our senses or when triggered by chemical
signals from neighbouring neurons. In response, a neuron fires an impulse, called the Action Potential –
a brief electrical charge that travels down a neuron, but what exactly is this?
In a neuron, there are dissolved ions inside the soma, and outside. These are primarily Na+, Cl-
and K+ ions. Although they are both found inside and out, they are in different concentrations depending
on what is happening with the neuron. Depending on what is happening with the neuron, these chemicals
may have to pass through the Cell Membrane. The cell membrane is porous, and selectively permeable.
Meaning that water and chemicals can diffuse in and out, but they cannot go as they please. There are
rules and regulations that they must follow.
This is the concentrations of chemicals when a neuron is at rest
More Negative than outside
More Positive than Inside
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This imbalance leads to an electrical charge of -70mV, causing the membrane to become polarized.
Even when a neuron is at rest, it is still receiving messages. These messages will change the concentration
of ions, and change the overall charge of the membrane. There are two different types of messages that
neurons receive that will change the concentration of ions.
Inhibitory: These messages tell the neurons not to fire. This message will increase the amount of
negative ions, causing the membrane to hyperpolarize to -76mV. The more negative a membrane, the
less likely it is to fire.
Excitatory: These messages tell the neuron to fire. Na+ ions will diffuse into the cell, increasing the
number of positive ions inside the cell. This causes the membrane to depolarize to -63mV. The more
positive the charge, the more likely it is to fire.
When will a neuron fire? A neuron will fire when it reaches its threshold of excitement, which is about
-50 mV. Large numbers of Na+ ions will rush into the cell and depolarizes the membrane. This change in
charge causes another axon channel to open, and then another, like a domino effect. This is the action
potential. After a neuron fires, it will go into a Refractory Period, where it is not possible for a neuron to
fire. During this period, Sodium-Potassium Pumps actively pump Na+ out and K+ in to repolarize the
membrane to -70mV.
2-3: How Neurons Communicate: How do nerve cells communicate with other nerve cells?
Neurons interweave so intricately that it was once believed that the axon of one nerve cell fused with the
dendrites of another to form an uninterrupted fabric of communication. However this was proven
incorrect, as it was noticed that neural messages taking an unexpectedly long time to travel a neural
pathway, inferring that there was a brief interruption in the transmission. This extremely tiny meeting
point between neurons is called the Synapse. If there is a gap between neurons, how do they convey
information to each other? That is the work of Neurotransmitters: chemical messengers that cross the
synaptic gaps between neurons. When an action potential reaches the terminal buttons of an axon found
on a Pre Synaptic Neuron, it causes the Synaptic Vesicles, “bags” that contain neurotransmitters, of a
neuron to burst open, releasing neurotransmitters into the synapse. The neurotransmitters attach
themselves to receptors that are found on the dendrites of a Post Synaptic Neuron and deliver their
The Fate of a Neurotransmitter: After a neurotransmitter has delivered its message, it detaches itself
from the receptor, and suffers one of two fates:
Reuptake: The neurotransmitter goes back to the neuron that released it. This is a form of recycling.
Degradation: Specialized enzymes will deactivate the neurotransmitter.
If a neurotransmitter is not degraded or taken back, it will deliver its message indefinitely and
overstimulate or overinhibit the nervous system.
2-4: How Neurotransmitters Influence us: How do neurotransmitters influence behavior, and how
do drugs and other chemicals affect neurotransmission?
Neurotransmitters have a profound impact on behavior and feelings. Specific neurotransmitters may
affect specific behaviors and emotions
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Some Neurotransmitters and Their Functions:
Neurotransmitter Function Example of Malfunctions
Acetylcholine (ACh) Enables muscles action, learning
With Alzheimer’s, ACh
producing neurons deteriorate
Dopamine Influences movement, learning,
attention, and emotion
Oversupply linked to
linked to tremors and decreased
mobility in Parkinson’s disease
Serotonin Affects mood, hunger, sleep, and
Undersupply linked to
depression. Some antidepressant
drugs raise serotonin levels
Norepinephrine Helps control Alertness and
Undersupply can depress mood.
A major inhibitory
Undersupply linked to seizures,
tremors, and insomnia
Glutamate A major excitatory
neurotransmitter involved in
Oversupply can overstimulate the
brain, producing migraines or
How Drugs and Other Chemicals Alter Neurotransmission: All chemicals that affect the brain produce
their effects in the synapse.
Inhibit: Blocks or reduces significance of a neurotransmitter
Facilitate: Aids in the release of a neurotransmitter.
Drugs can be either Agonists or Antagonists.
Agonist: Mimics the effect of a neurotransmitter, enhances the effects, or facilitates the release of a
Antagonist: Binds to receptors, but blocks the neurotransmitters functioning. Antagonists are similar
enough to neurotransmitters to bind to receptors, but not similar enough to produce their effects.
2-5: The Nervous System: What are the functions of the nervous system’s main divisions, and what
are the three main types of neurons?
The nervous system is responsible for taking information from the world, making decisions, and sending
information back to the body’s tissues. The brain and spinal cord form the Central Nervous System,
which is the body’s decision maker. The Peripheral Nervous System is responsible for gathering
information and for transmitting central nervous system information to other body parts.
The Peripheral Nervous System: This system connects the body to the CNS, and vice versa. There are
to components to the peripheral nervous system.
Somatic Nervous System: Enables voluntary control of skeletal muscles and collects information from
senses via sensory neurons and relays that information to the central nervous system.
Autonomic Nervous System: Controls glands and the muscles of the internal organs. The ANS is
responsible for the rhythmic beating of the heart, glandular activity, and digestion. The ANS serves two
important, basic functions:
Sympathetic Nervous System: Enables, arouses, and mobilizes the body’s resources to that the body can
take action. This is also known as the “fight-or-flight” response.
Parasympathetic Nervous System: Calms the body and helps to conserve energy. Also helps the body
These two systems work together to help ensure that the body stays at a steady internal state.
2-6: The Endocrine System: How does the endocrine system transmit information and interact with
the nervous system?
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